Does dairy alone work to prevent and lower high blood pressure?
For the last four years, the Dietary Approaches to Stop Hypertension (DASH) diet has ranked #1 in a U.S. News & World Report ranking of 32 diets. Why? Because the DASH diet doesn’t involve deprivation and it exemplifies the 2010 Dietary Guidelines for Americans – the current dietary intake recommendations based on years of science.
What’s the DASH diet?
The DASH diet, most renowned for preventing and lowering high blood pressure, has garnered more research attention than any other diet. The eating plan is rich in low-fat dairy, fruits and vegetables – three servings of low-fat dairy and 8-10 servings of fruits and vegetables to be exact – while providing nutrient-rich whole grains, fish, poultry, beans, seeds and nuts. The theory is that nutrients such as calcium, potassium, magnesium, protein and fiber (found in dairy foods, fruits and vegetables) are crucial for preventing and lowering high blood pressure.
Research on the DASH diet has shown that a diet high in fruits and vegetables alone doesn’t have the same effect on blood pressure regulation as a diet high in fruits, vegetables and dairy foods. So the question becomes, does dairy alone work to prevent and lower high blood pressure?
A study published in May in the American Journal of Clinical Nutrition set out to answer this question. The aim of the study was to look at the effects of the solitary addition of non-fat dairy foods on blood pressure. The study participants were middle-aged and older adults with stage one hypertension, and dairy consumption below the recommended three servings per day. Through a randomized crossover design, study participants were assigned either to a diet high in dairy foods (four servings per day) or a no-dairy diet for four weeks.
Researchers found that the high dairy intake led to increased consumption of calcium, magnesium, potassium, vitamin D and protein, and a decrease in both systolic blood pressure and pulse pressure (two markers of cardiovascular disease risk) by week three of eating the high-dairy diet. They did not see any changes in diastolic blood pressure.
This research adds to the totality of the evidence on dairy foods and blood pressure – a very compelling case for adequate dairy consumption on the reduction in risk for high blood pressure in people with hypertension and pre-hypertension. And while the evidence is strong, the researchers acknowledge that more research is needed. Specific research is needed to look at the minimal and optimal dose of dairy necessary to see blood pressure reductions, to look at ethnic differences in blood pressure response to dairy, and to assess the combined effects of dairy and other lifestyle modifications (e.g., regular exercise). Questions also remain as to the mechanism by which dairy foods lower blood pressure – i.e. what nutrient/component in dairy foods modulates this effect and/or is there a specific dairy food that contributes more than another to this reduction in blood pressure.
The good news: Dairy as part of a balanced diet continues to show positive benefits on overall health, specifically on preventing and lowering high blood pressure. Regardless of the individual nutrients or mechanism by which dairy assists in blood pressure regulation, consumers of all ages should continue to enjoy the recommended three servings of low-fat or fat-free dairy foods every day for optimal health.